Accuracy of body size estimation: Role of biopsychosocial variables

This study evaluated factors related to the perceptual disturbances of body image. Using a digital body image computer program, 191 participants (107 women, 82 men) adjusted an image of their body to the perceived actual size at five body regions; chest, waist, hips, thighs and calves. A neutral object (a vase) was also adjusted to partial out the level of perceptual distortion present with a neutral object. Men and women overestimated the size of the neutral object and their body image. Among women, overestimation was primarily predicted by high levels of depression, and media and peer influences to be thinner and increase muscles. Among men, overestimation was predicted by high BMI, media influences to lose weight and increase muscles, and peer influences to increase muscles. These findings suggest that perceptual accuracy of body image is primarily predicted by biopsychosocial influences.

Comparative accuracy of magnetic resonance imaging and ultrasonography in confirming clinically diagnosed patellar tendinopathy

Background: Diagnosis of patellar tendinopathy is based primarily on clinical examination; however, it is commonplace to image the patellar tendon for diagnosis confirmation, with the imaging modalities of choice being magnetic resonance imaging (MRI) and ultrasonography (US). The comparative accuracy of these modalities has not been established.

Hypothesis: Magnetic resonance imaging and US have good (>80%) accuracy and show substantial agreement in confirming clinically diagnosed patellar tendinopathy.

Study Design: Cohort study (diagnosis); Level of evidence, 2.

Methods: Magnetic resonance imaging and US (gray scale [GS-US] and color Doppler [CD-US]) features of 30 participants with clinically diagnosed patellar tendinopathy and 33 activity-matched, asymptomatic participants were prospectively compared. Accuracy, sensitivity, specificity, positive and negative predictive values, and the likelihood of positive and negative test results were determined for each technique.

Results: The accuracy of MRI, GS-US, and CD-US was 70%, 83%, and 83%, respectively (P = .04; MRI vs GS-US). The likelihood of positive MRI, GS-US, and CD-US was 3.1, 4.8, and 11.6, respectively. The MRI and GS-US had equivalent specificity (82% vs 82%; P = 1.00); however, the sensitivity of GS-US was greater than MRI (87% vs 57%; P = .01). Sensitivity (70% vs 87%; P = .06) and specificity (94% vs 82%; P = .10) did not differ between CD-US and GS-US.

Conclusions: Ultrasonography was more accurate than MRI in confirming clinically diagnosed patellar tendinopathy. GS-US and CD-US may represent the best combination for confirming clinically diagnosed patellar tendinopathy because GS-US had the greatest sensitivity, while a positive CD-US test result indicated a strong likelihood an individual was symptomatic.

Dielectric characterization of conducting textiles using free space transmission measurements: accuracy and methods for improvement

The dielectric behaviour of in-situ polymerized thin polypyrrole (PPy) films on synthetic textile substrates were obtained in the 1–18 GHz region using free space transmission and reflection methods. The PPy/para-toluene-2-sulphonic acid (pTSA) coated fabrics exhibited an absorption dominated total shielding effectiveness (SE) of up to −7.34 dB, which corresponds to more than 80% of incident radiation. The permittivity response is significantly influenced by the changes in ambient conditions, sample size and diffraction around the sample. Mathematical diffraction removal, time-gating tools and high gain horns were utilized to improve the permittivity response. A narrow time-gate of 0.15 ns produced accurate response for frequencies above 6.7 GHz and the high gain horns further improved the response in the 7.5–18 GHz range. Errors between calculated and measured values of reflection were most commonly within 2%, indicating good accuracy of the method.

A novel episodic associative memory model for enhanced classification accuracy

A novel approach to Episodic Associative Memory (EAM), known as Episodic Associative Memory with a Neighborhood Effect (EAMwNE) is presented in this paper. It overcomes the representation limitations of existing episodic memory models and increases the potential for their use in practical application.

Generality is predictive of prediction accuracy

During knowledge acquisition multiple alternative potential rules all appear equally credible. This paper addresses the dearth of formal analysis about how to select between such alternatives. It presents two hypotheses about the expected impact of selecting between classification rules of differing levels of generality in the absence of other evidence about their likely relative performance on unseen data. It is argued that the accuracy on unseen data of the more general rule will tend to be closer to that of a default rule for the class than will that of the more specific rule. It is also argued that in comparison to the more general rule, the accuracy of the more specific rule on unseen cases will tend to be closer to the accuracy obtained on training data. Experimental evidence is provided in support of these hypotheses. We argue that these hypotheses can be of use in selecting between rules in order to achieve specific knowledge acquisition objectives.

Implications of accuracy, sensitivity, and variability of body size estimations to disordered eating

The current study was conducted to investigate the relationships between body size estimations and disordered eating symptomatology. The method of constant stimuli was used to derive three measures of self-perceived body size in 93 women: (1) accuracy of body size estimations (body image distortion); (2) sensitivity in discriminating body size within blocks of trials (body image sensitivity); and (3) variability in making body size estimations between blocks of trials (body image variability). Participants also completed measures of disordered eating. Although body image distortion correlated with dietary restraint and eating concern, body image variability accounted for additional variance in these variables, as well as variance in binge eating. The relationships involving body image variability were found to be mediated by body dissatisfaction and internalization of the thin ideal. Together, these results are consistent with the proposition that body image variability is a significant factor in disordered eating.

The effect of training in reduced energy density eating and food self-monitoring accuracy on weight loss maintenance

Background:
Failure to maintain weight losses in lifestyle change programs continues to be a major problem and warrants investigation of innovative approaches to weight control.
Objective:
The goal of this study was to compare two novel group interventions, both aimed at improving weight loss maintenance, with a control group.
Methods and Procedures:
A total of 103 women lost weight on a meal replacement–supplemented diet and were then randomized to one of three conditions for the 14-week maintenance phase: cognitive-behavioral treatment (CBT); CBT with an enhanced food monitoring accuracy (EFMA) program; or these two interventions plus a reduced energy density eating (REDE) program. Assessments were conducted periodically through an 18-month postintervention. Outcome measures included weight and self-reported dietary intake. Data were analyzed using completers only as well as baseline-carried-forward imputation.
Results:
Participants lost an average of 7.6 plusminus 2.6 kg during the weight loss phase and 1.8 plusminus 2.3 kg during the maintenance phase. Results do not suggest that the EFMA intervention was successful in improving food monitoring accuracy. The REDE group decreased the energy density (ED) of their diets more so than the other two groups. However, neither the REDE nor the EFMA condition showed any advantage in weight loss maintenance. All groups regained weight between 6- and 18-month follow-ups.
Discussion:
Although no incremental weight maintenance benefit was observed in the EFMA or EFMA + REDE groups, the improvement in the ED of the REDE group's diet, if shown to be sustainable in future studies, could have weight maintenance benefits.

Sexing accuracy and indicators of maturation status in captive Murray cod Maccullochella peelii peelii using non-invasive ultrasonic imagery

Macroscopic- and histological-based assessments of gonad condition were compared with ultrasound images to determine the feasibility of this technology as a non-invasive diagnostic tool for identifying sex and assessing maturation status of Murray cod. Four age-classes (1⁺, 2⁺, 3⁺ and 6⁺ years), were sub-sampled at monthly intervals throughout their annual reproductive cycle and scanned with a 5 MHz linear transducer. An interpretation of sex was made from the resulting images and maximum cross-sectional gonad diameter and area were recorded. Fish were subsequently dissected to confirm gender, and the weights and maturation status of gonads determined and then compared with their respective image profile. Ovaries of females were usually a distinctive feature in ultrasound images, being particularly obvious in older and/or more developed fish. In contrast, the identification of male testis was more problematic. Nonetheless, identifying sex from ultrasound images was consistently achieved by recording the presence/absence of a female ovary (96% total sexing accuracy). Maximum cross-sectional ovary diameter and area were highly correlated with gonad weight (r² = 0.90 and 0.89, respectively) suggesting that indices of maturation status, comparable to the gonadosomatic index (GSI), can be obtained non-destructively from ultrasound scans of females. A less distinct relationship occurred between these dimensions and weight of testes (r² = 0.41). Significant increases (P < 0.05) in mean gonad index (GI, calculated from gonad diameter) occurred for most gonad development stages. However, differences in mean GI between maturation stages were confounded by phenotypic variability, indicating that GI may be limited to population level studies. Nevertheless, ultrasound images of ovaries at each development stage were visually distinctive and enabled qualitative evaluations of maturity, thereby complementing quantitative GI assessments. Repeated serial-monitoring of the same population using ultrasound appears to have great potential for tracking maturation-induced changes in broodfish.

Straight to the source : an exploratory study of Australia's regional newspaper journalists' checks on validity and accuracy of sources

This paper reports on an exploratory study that examined whether journalists
undertake the vital role of checking the validity and accuracy of information
supplied to them in media releases. It also monitored how much information
journalists used from press releases in their published work. The study followed Gandy's information subsidy theory by surveying 10 local government media relations officers who regularly issued media releases via
electronic mail or facsimile to a sample of 14 rural/regional newspapers. The data analysed found that rural/regional journalists were not adequately verifying information supplied in media releases and using a significant amount of this information verbatim.

Accuracy and precision assesment of stochastic simulation tools for springback variation

The sheet forming industry is plagued by inherent variations in its many input variables, making quality control and improvements a major hurdle. This is particularly poignant for Advanced High Strength Steels (AHSS), which exhibit a large degree of property variability. Current FE-based simulation packages are successful at predicting the manufacturability of a particular sheet metal components, however, due to their numerical deterministic nature are inherently unable to predict the performance of a real-life production process. Though they are now beginning to incorporate the stochastic nature of production in their codes. This work investigates the accuracy and precision of a current stochastic simulation package, AutoForm Sigma v4.1, by developing an experimental data set where all main sources of variation are captured through precise measurements and standard tensile tests. Using a Dual Phase 600Mpa grade steel a series of semi-cylindrical channels are formed at two Blank Holder Pressure levels where the response metric is the variation in springback determined by the flange angle. The process is replicated in AutoForm Sigma and an assessment of accuracy and precision of the predictions are performed. Results indicate a very good correspondence to the experimental trials, with mean springback response predicted to within 1 ° of the flange angle and the interquartile spread of results to within 0.22°.

Recurrent events counted in evaluations of predictive accuracy

Objectives: To describe an alternate approach for the calculation of sensitivity and specificity when analyzing the accuracy of screening tools, which can be used when standard calculations may be inappropriate. Sensitivity^ER (ER denoting event rate) is the number of events correctly predicted, divided by the total number of events. Specificity^ER is the amount of time that study participants are predicted to be event negative, divided by the total amount of participant observed time. Variance estimates for these statistics are constructed by bootstrap resampling, taking into account event dependence.

Methods: Standard and alternate approaches for calculating sensitivity and specificity were applied to hospital falls risk screening tool data. In this application, the outcome of interest was a recurrent event, there were multiple applications of the screening tool, delays in screening tool  completion, and patients' follow-up durations were unequal.

Results: Application of sensitivity^ER and specificity^ER to this data not only provided a clearer description of the screening tool's overall accuracy, but also allowed examination of accuracy over time, accuracy in predicting specific event numbers, and evaluation of the added value that screening tool reapplications may have.

Conclusion: Sensitivity^ER and specificity^ER provide a valuable approach to screening tool evaluation in the clinical setting.

Design-related bias in hospital fall risk screening tool predictive accuracy evaluations: systematic review and meta-analysis.

Introduction: Fall risk screening tools are frequently used as a part of falls prevention programs in hospitals. Design-related bias in evaluations of tool predictive accuracy could lead to overoptimistic results, which would then contribute to program failure in practice.

Methods: A systematic review was undertaken. Two blind reviewers assessed the methodology of relevant publications into a four-point classification system adapted from multiple sources. The association between study design classification and reported results was examined using linear regression with clustering based on screening tool and robust variance estimates with point estimates of Youden Index (= sensitivity + specificity - 1) as the dependent variable. Meta-analysis was then performed pooling data from prospective studies.

Results: Thirty-five publications met inclusion criteria, containing 51 evaluations of fall risk screening tools. Twenty evaluations were classified as retrospective validation evaluations, 11 as prospective (temporal) validation evaluations, and 20 as prospective (external) validation evaluations. Retrospective evaluations had significantly higher Youden Indices (point estimate [95% confidence interval]: 0.22 [0.11, 0.33]). Pooled Youden Indices from prospective evaluations demonstrated the STRATIFY, Morse Falls Scale, and nursing staff clinical judgment to have comparable accuracy.

Discussion: Practitioners should exercise caution in comparing validity of fall risk assessment tools where the evaluation has been limited to retrospective classifications of methodology. Heterogeneity between studies indicates that the Morse Falls Scale and STRATIFY may still be useful in particular settings, but that widespread adoption of either is unlikely to generate benefits significantly greater than that of nursing staff clinical judgment.